>>1.First and most obviously, if Spain leaves the euro its debt burden will soar

Unlike Greece's restructured debt which is subject to British law, Spanish debt will be converted into pesetas. if you have any problems with that, you will have to go to a Spanish court to argue your case. The Spanish Central bank will print and support debt prices.

The answer to all that is Buffet's import-export credits. If push comes to shove and Euro is at risk, this is the best solution without having to ruin the common currency or impose capital controls.http://bit.ly/1omNvg3

The viability of the mine is determined on whether it can produce cash. Whatever development costs they incurred is sunk costs. Admin. costs are distributed over many mines. Fresnillo has mines that can be profitable with spot price between AISC and cash cost.